| d1 | d2 | Straight | Advantage | Disadvantage |
|---|---|---|---|---|
| 1 | 1 | 1 | 1 | 1 |
| 1 | 2 | 1 | 2 | 1 |
| 1 | 3 | 1 | 3 | 1 |
| 1 | 4 | 1 | 4 | 1 |
| 1 | 5 | 1 | 5 | 1 |
| 1 | 6 | 1 | 6 | 1 |
| 1 | 7 | 1 | 7 | 1 |
Taking Advantage
An Analysis of Advantage/Disadvantage in the D20 System
Mick Cooney mickcooney@gmail.com
Background
Who Am I?
Dublin Data Science
Goals
Test Intuition
Simulate Mechanisms
Illustrate Typical Examples
Setting Up
Discrete space
No need for simulation
\[\begin{eqnarray*} 1d20 &\rightarrow& 20 \text{ possible outcomes} \\ 2d20 &\rightarrow& 400 \text{ possible outcomes} \end{eqnarray*}\]
Create table of outcomes for 2d20.
\[\begin{eqnarray*} \text{Straight: } &\rightarrow& \text{ use first die} \\ \text{Adv/Disadv: } &\rightarrow& \text{ use max/min of two dice} \\ \text{ROLL(P/M)#: } &\rightarrow& \text{ adjust first die} \end{eqnarray*}\]
Analysing Failure
The Champion
Subclass of Fighter
Critical Hit on 19 or 20
What is the impact of advantage / disadvantage
| Roll Type | Target | Success Prob | Failure Prob |
|---|---|---|---|
| Straight | 19 | 0.1000 | 0.9000 |
| Straight | 20 | 0.0500 | 0.9500 |
| Advantage | 19 | 0.1900 | 0.8100 |
| Advantage | 20 | 0.0975 | 0.9025 |
| Disadvantage | 19 | 0.0100 | 0.9900 |
| Disadvantage | 20 | 0.0025 | 0.9975 |
Opposed Rolls
Resolve Contests
Both Roll 1d20, add bonus
Discrete Space
Bigger and messier
Use simulation
Probabilities Comparison
Thank You!
This talk…
https://github.com/kaybenleroll/data_workshops/talk_gaming_dndadv_202301